1. Field of the Invention
The present invention relates to image recording media used in ink-jet printing, heat sensitive printing, thermal development printing, silver halide photographic printing and, in particular, printing, that prevents an occurrence of edge voids leading to uneven gloss recognized as an image defect, and a method of recording images on the image recording media.
2. Description of Related Art
Typically, image recording methods used in electrophotography have a problem with a deterioration in image quality resulting from an occurrence of edge voids (an image defect as uneven gloss resulting from lusterless boundaries between high density parts and white parts. There have been proposed a variety of approaches to solving the problem by governing viscoelasticity of a thermoplastic resin of an image receptor layer. For example, Japanese Unexamined Patent Publication No. 2002-341580 discloses an image printing or recording sheet comprising a paper sheet substrate and an image receptor layer coated on the paper sheet substrate at least one side thereof that contains a thermoplastic resin having a 10-points average surface roughness (Rz) in a range of from 0.1 to 3.0 mμ and a storage modulus (G′) at 160° C. in a range of from 1×103 to 1×106 Pa. Japanese Unexamined Patent Publication No. 10-239889 discloses an image printing or recording sheet comprising a paper sheet substrate and a toner image receptor layer that is coated on the paper sheet substrate and has a storage modulus (G′) and a loss modulus (G″) both in a range of from 1×102 to 1×105 Pa, respectively, at a fixing temperature of toner. Japanese Unexamined Patent Publication No. 2000-131868 discloses an image receptor layer coated on a paper sheet substrate at either one or both sides thereof. A binding resin forming the image receptor layer has a storage modulus (G′) of 1×106 Pa or higher at a temperature lower than 40° C. and satisfies the following conditions:G′130/G′200≦9.0 and G′130≦1×103 Pa.where G′130 is the storage modulus at 130° C. and G′200 is the storage modulus at 200° C.
Further, Japanese Unexamined Patent Publication No. 2000-181115 discloses an image printing or recording sheet comprising an image receptor layer that is coated on a paper sheet substrate at either one or both sides thereof and contains a binder resin having a storage modulus (G′) of 1×104 Pa or higher at 130° C. and a storage modulus (G′) of 1×102 Pa or higher at 200° C.
However, since viscoelasticity of thermoplastic resins of the conventional image receptor layers are measured at a programming rate (a rate of temperature-rise) of 2° to 10° C./min which is considerably low as compared with programming rates of practical toner fixing system such as comprising a fixing roller or a fixing belt that is generally in a range of from 10° to 100° C./sec, the measurements of viscoelasticity are not always in line with real quantitative deformation of the image receptor layers, technical improvement in viscoelasticity measurement is strongly desired.